Determining a power control group boundary of a power control group

ABSTRACT

Determining a power control group boundary includes receiving a plurality of samples having power control groups, where each power control group corresponds to a time period. The following are repeated for a predetermined number of iterations: a window is set at a point of a sample; a number of power control bits within the window at the point is determined; and the window is moved to a point of a next sample. A point at which the window has the largest number of power control bits is identified. A power control group boundary is determined in accordance with the window at the identified point.

TECHNICAL FIELD

This invention relates generally to the field of wireless communicationsand more specifically to determining a power control group boundary of apower control group.

BACKGROUND

A transmitting communication device may have multiple antenna elementsthat transmit signals to communicate information. A receivingcommunication device extracts the information from the transmittedsignals. Multiple antenna elements may enhance spectral efficiency,allowing for more users to be simultaneously served over a givenfrequency band. The transmitted signals, however, propagate alongdifferent paths and may reach the receiving communication device withdifferent phases that destructively interfere. It is generally desirableto reduce interference of transmitted signals.

SUMMARY OF THE DISCLOSURE

In accordance with the present invention, disadvantages and problemsassociated with previous techniques for communicating signals usingmultiple antenna elements may be reduced or eliminated.

According to one embodiment of the present invention, determining apower control group boundary includes receiving a plurality of sampleshaving power control groups, where each power control group correspondsto a time period. The following are repeated for a predetermined numberof iterations: a window is set at a point of a sample; a number of powercontrol bits within the window at the point is determined; and thewindow is moved to a point of a next sample. A point at which the windowhas the largest number of power control bits is identified. A powercontrol group boundary is determined in accordance with the window atthe identified point.

Certain embodiments of the invention may provide one or more technicaladvantages. A technical advantage of one embodiment may be that amodification may be determined according to a quality indicator. Themodification may be applied to signals transmitted by multiple antennaelements in accordance with a time boundary, which may improve thequality of the transmitted signals.

Certain embodiments of the invention may include none, some, or all ofthe above technical advantages. One or more other technical advantagesmay be readily apparent to one skilled in the art from the figures,descriptions, and claims included herein.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention and itsfeatures and advantages, reference is now made to the followingdescription, taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 is a block diagram of one embodiment of a communication networkthat includes one or more transmitting communication devices and one ormore receiving communication devices that communicate via a wirelesslink;

FIG. 2 is a block diagram of another embodiment of a communicationnetwork that includes one or more transmitting communication devices andone or more receiving communication devices that communicate via awireless link;

FIG. 3 is a block diagram of one embodiment of a receiving communicationdevice that includes a quality indicator generator that may be used inFIG. 1;

FIG. 4 is a block diagram of one embodiment of a transmittingcommunication device that includes a signal modifier that may be used inFIG. 1;

FIG. 5 is a block diagram of one embodiment of a transmitter system thatmay be used with the communication device of FIG. 2;

FIG. 6 is a block diagram of one embodiment of a signal modifier;

FIG. 7 is a block diagram of another embodiment of a signal modifier;

FIG. 8 is a block diagram of one embodiment of a vector modulator;

FIG. 9 is a flowchart illustrating one embodiment of a method forapplying a modification to a signal in accordance with a time boundarythat may be used with any suitable communication device;

FIG. 10 is a flowchart illustrating an example method for applying amodification to a signal in accordance with a time boundary that may beused with any suitable communication device;

FIG. 11 is a flowchart illustrating another example method for applyinga modification to a signal in accordance with a time boundary that maybe used with any suitable communication device;

FIG. 12 is a flowchart illustrating an example method for calculating acomplex weighting that may be used with any suitable communicationdevice;

FIG. 13 is a flowchart illustrating another example method forcalculating a complex weighting that may be used with any suitablecommunication device;

FIG. 14 is a flowchart illustrating another example method forcalculating a complex weighting that may be used with any suitablecommunication device; and

FIGS. 15 and 16 are diagrams illustrating one embodiment of a slidingwindow technique for determining a time boundary corresponding to aquality indicator.

DETAILED DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention and its advantages are bestunderstood by referring to FIGS. 1 through 16 of the drawings, likenumerals being used for like and corresponding parts of the variousdrawings.

FIG. 1 is a block diagram of one embodiment of a communication network10 that includes one or more transmitting communication devices 20 a andone or more receiving communication devices 20 b that communicate via awireless link 24. According to the embodiment, a communication device 20a receives a quality indicator describing the quality of wireless link24, and determines a modification according to the quality indicator.Communication device 20 a modulates signals for transmission tocommunication device 20 b using the modification in accordance with atime boundary. In certain cases, modulating the signals in accordancewith a time boundary may synchronize modification of the signal with aquality indicator describing the link quality in response to themodification.

According to the illustrated embodiment, a communication device 20comprises any device operable to communicate information via signals toone or more other communication devices. For example, communicationdevice 20 may comprise a subscriber communication device or a basestation. A subscriber communication device may comprise any deviceoperable to communicate with a communication system, for example, apersonal digital assistant, a cellular telephone, a mobile handset, orany other device suitable for communicating data to and from a basestation. A subscriber communication device may support, for example,simple Internet Protocol (IP), mobile IP, or any other suitablecommunication protocol. A subscriber communication device may utilize,for example, General Packet Radio Service (GPRS) technology or any othersuitable mobile communication technology.

A base station typically includes a base transceiver station and a basestation controller. The base transceiver station typically communicatessignals to and from one or more subscriber communication devices. Thebase station controller manages the operation of the base transceiverstation. The base station provides a subscriber communication deviceaccess to a communication network that allows the subscribercommunication device to communicate with other networks or devices. Acommunication network may comprise all or a portion of public switchedtelephone network (PSTN), a public or private data network, a local areanetwork (LAN), a metropolitan area network (MAN), a wide area network(WAN), a global computer network such as the Internet, a wireline orwireless network, a local, regional, or global communication network, anenterprise intranet, other suitable communication link, or anycombination of the preceding.

Transmitting communication device 20 a, receiving communication device20 b, or both may include one or multiple antenna elements, where eachantenna element is operable to receive, transmit, or both receive andtransmit a signal. Multiple antenna elements may provide for aseparation process known as spatial filtering, which may enhancespectral efficiency, allowing for more users to be served simultaneouslyover a given frequency band.

Communication devices 20 may communicate with one or more subscribercommunication devices, one or more base stations, one or more othercommunication devices, or any combination of the preceding.Communication devices 20 may communicate according to any suitablecommunication protocol. For example, communication devices 20 maycommunicate according to any suitable code division multiple access(CDMA) protocol such as CDMA-IS-95, CDMA 2000 1XRTT, CDMA 2000 3X, CDMAEV-DO, wideband CDMA (WCDMA), CDMA EV-DV, or other suitable CDMAprotocol. Examples of other protocols include any generation UniversalMobile Telecommunications System (UMTS), hybrid multiple accessprotocols, 802.xx protocols, time division multiple access (TDMA)protocols, and frequency division multiple access (FDMA) protocols.

A communication link between communication devices 20 a and 20 b such aswireless link 24 is typically a radio frequency link that may becellular in network organization. Wireless link 24 may be used tocommunicate a signal between communication devices 20 a and 20 b. Asignal may comprise data packets communicating information such as data,video, voice, multimedia, any other suitable type of information, or anycombination of the preceding. Wireless link 24 may be configuredaccording to a Multiple-Input-Multiple-Output (MIMO) communicationsprotocol.

According to the illustrated embodiment, communication device 20 bgenerates one or more quality indication signals from whichcommunication device 20 a determines the modification. Communicationdevice 20 b includes a quality indicator generator 30 a that generatesone or more quality indicators that reflect the quality of wireless link24. The quality of a communication link may be determined from thecharacteristics of a signal received from communication device 20 a, forexample, the signal-to-noise-ratio, signal-to-interference-ratio, signalpower, signal timing stability, signal envelop, other suitable signalcharacteristic, or any combination of the preceding. A quality indicatormay reflect changes in the quality due to a modification applied bycommunication device 20 a.

A quality indicator reflecting quality may comprise, for example, apower control bit, bit error rate indicator, frame error rate indicator,packet error rate indicator, other suitable quality indicator, or anycombination of the preceding. As an example, a power control bitinstructs a communication device 20 to increase or decrease transmissionpower. Quality indicator generator 30 a may transmit the qualityindicator via a quality indication signal. A quality indication signalmay comprise a signal having information about the quality of thecommunication link, for example, a power control signal of any suitableCDMA protocol, error rate messages, other suitable quality indicationsignal, or any combination of the preceding. As an example, a powercontrol signal may include one or more power control bits. A qualityindication signal may be transmitted at any suitable rate, for example,once every 1.25 ms for cdmaOne (IS-95)/CDMA2000 or once every 0.66 msfor WCDMA.

Communication device 20 a includes a signal modifier 32 a that modifiesa pre-transmission signal in accordance with one or more qualityindicators of a received quality indication signal. The signals may bemodified to increase constructive interference or reduce destructiveinterference. A modification may refer to one or more adjustments of oneor more modulation features of one or more signals. A modulation featurerefers to a feature of a signal that may be modulated, for example, aphase, amplitude, frequency, timing, other suitable modulation feature,or any combination of the preceding. A modification may be applied to asignal or to frequency subbands of a signal. As an example, a set of oneor more adjustments may be applied to a signal. As another example,multiple sets of one or more adjustments may be applied to a signal,where each set is applied to a different subband of the signal.

Signal modifier 32 a determines a modification in accordance with theone or more quality indicators. For example, signal modifier 32 a maycalculate a complex weighting based on the quality indicators, which maybe used to adjust the magnitude and phase of the signal. The complexweighting provided may be based on one or more modification featuressuch as the total power of the transmitted signal, the phase rotationassociated with each antenna element, the power ratio associated witheach antenna element, the time delay associated with each antennaelement, other feature, or any combination of the preceding.

Signal modifier 32 a modifies a signal by applying the determinedmodification to produce one or more modified pre-transmission signals.The number of pre-transmission signals may correspond to the number ofantenna elements of a transmit antenna of communication device 20 a, anda pre-transmission signal may be associated with an antenna element. Thenumber of pre-transmission signals may, however, be less than, equal to,or greater than the number of antenna elements. Signal modifier 32 a maymodify a signal in any suitable manner. For example, signal modifier 32a may manipulate the weights of the various power amplifiers that feedtheir respective antenna elements of the transmit antenna.

Signal modifier 32 a applies the modification in accordance with a timeboundary of a time period such as a CDMA power control group (PCG).According to CDMA, traffic channels are subdivided into 20-ms frames.Each frame is further subdivided into 16 power control groups, eachlasting 1.25 ms. In general, a set of one or more power control bits issent for each power control group. In practice, a power control bit setmay be sent at any of a number of times within a power control group.Signal modifier 32 a may apply a modification in response to a timeboundary in order to apply one modification per time period. Themodification may be applied at any suitable point of the time period.Applying one modification per time period may synchronize modificationof the signal with a quality indicator describing the link quality inresponse to the modification. Synchronization may avoid a qualityindicator describing the link quality in response to less than one ormore than one modification. Signal modifier 32 a may estimate where thetime boundaries are located using a technique described in more detailwith reference to FIGS. 15 and 16.

Communication device 20 a transmits the modified pre-transmissionsignals that form a combined signal, which may be received bycommunication device 20 b or other suitable communication device 20. Themodification of the pre-transmission signals may provide for improvedcommunication of the signals. For example, if the rate at which thesignals are controlled exceeds the rate of fading, then the signal maybe received at a relatively constant rate of power at a substantiallyoptimized power. Other aspects of the communication may be optimized orimproved, for example, reduced medium contention, reduced probability ofdetection or interception, improved network load balance, reduced RFinterference, other aspect, or any combination of the preceding.

Alterations or permutations such as modifications, additions, oromissions may be made to communication network 10 without departing fromthe scope of the invention. Additionally, operations of communicationnetwork 10 may be performed using any suitable logic comprisingsoftware, hardware, other logic, or any suitable combination of thepreceding. As used in this document, “each” refers to each member of aset or each member of a subset of a set.

FIG. 2 is a block diagram of another embodiment of a communicationnetwork 40 that includes one or more transmitting communication devices20 c and one or more receiving communication devices 20 d thatcommunicate via a wireless link 24. A communication device 20 ccalculates a quality indicator describing the quality of wireless link24, and determines a modification according to the quality indicator.Communication device 20 c modulates signals for transmission tocommunication device 20 d using the modification in accordance with atime boundary. In certain cases, modulating the signals in accordancewith a time boundary may synchronize modification of the signal with aquality indicator describing the link quality in response to themodification.

According to one embodiment, communication device 20 c includes aquality indicator generator 30 b and a signal modifier 32 b. Qualityindicator generator 30 b generates one or more quality indicators thatreflect the quality of wireless link 24. The quality of a communicationlink may be determined in any suitable manner. Signal modifier 32 bmodifies a pre-transmission signal in accordance with one or morequality indicators. Signal modifier 32 b may determine a modification inaccordance with the quality indicator as described with reference toFIG. 1. Signal modifier 32 b may modify a signal by applying thedetermined modification in accordance with a time boundary as describedwith reference to FIG. 1 to produce one or more modifiedpre-transmission signals.

Alterations or permutations such as modifications, additions, oromissions may be made to communication network 40 without departing fromthe scope of the invention. Additionally, operations of communicationnetwork 40 may be performed using any suitable logic comprisingsoftware, hardware, other logic, or any suitable combination of thepreceding.

FIG. 3 is a block diagram of one embodiment of a receiving communicationdevice 400 that includes a quality indicator generator 414 that may beused in network 10 of FIG. 1. Communication device 400 includes areceiver (Rx) 410 and a transmitter (Tx) 420 coupled as shown. Receiver410 includes an antenna 411, a demodulator 412, a quality estimator 413,and a quality indicator generator 414 coupled as shown. Transmitter 420includes a modulator 421, multiplexer 422, a power amplifier (PA) 423,and an antenna 424 coupled as shown.

Antenna 411 receives signals, which are demodulated by demodulator 412.Quality estimator 413 estimates a quality of the communication linkbetween communication device 400 and another communication device 20 aaccording to the received signal. Quality indicator generator 414generates a quality indicator that reflects the determined quality. Thequality indicator may be provided to the other communication device 20 ausing a quality indication signal. Modulator 421 modulates a transmitsignal, and multiplexer 422 multiplexes the transmit signal and thequality indication signal from quality indicator generator 414. Poweramplifier 423 amplifies the transmit signal, and antenna 424 transmitsthe signal.

Alterations or permutations such as modifications, additions, oromissions may be made to communication device 400 without departing fromthe scope of the invention. For example, communication device 400 mayhave more, fewer, or other modules. Moreover, the operations ofcommunication device 400 may be performed by more, fewer, or othermodules. Additionally, operations of communication device 400 may beperformed using any suitable logic comprising software, hardware, otherlogic, or any suitable combination of the preceding.

FIG. 4 is a block diagram of one embodiment of a transmittingcommunication device 120 that includes a signal modifier 122 that may beused in network 10 of FIG. 1. Communication device 120 may include anapplication subsystem 126, a baseband subsystem 121, a signal modifier122, a radio subsystem 123, a receive antenna 124, and one or moretransmit antennas 125 coupled as shown.

Application subsystem 126 processes receive signals to extractinformation communicated in the receive signals, and processes transmitsignals for transmission to communicate information. Baseband subsystem121 includes a modulator 140 that modulates signals and a demodulator129 that demodulates signals. Signal modifier 122 modulates one or morepre-transmission signals in accordance with one or more qualityindicators. Radio subsystem 123 includes a receiver 127 that receivessignals from receive antenna 124 and a transmitter 128 that sendssignals to one or more transmit antennas 125. Radio subsystem 123 mayinclude a duplexer/diplexer that separates different bands such ascellular service from Personal Communication Service (PCS) bands,receive from transmit bands, or both. Receive antenna 124 receivessignals and may have one or more antenna elements, and a transmitantenna 125 transmits signals and may have one or more antenna elements.Moreover, a common antenna may be used as both a receive and transmitantenna.

According to one embodiment of operation, receiver 127 receives a signalfrom receive antenna 124. Demodulator 129 demodulates signal 141 toproduce a demodulated signal 142 and to extract one or more qualityindicators sent from the other side of the wireless link. Signal 142 isprovided to application subsystem 126. The extracted quality indicatorsare provided to signal modifier 122 via a quality indication signal 143.

Application subsystem 126 generates an unmodulated transmit signal 144that may include information and sends signal 144 to modulator 140.Modulator 140 modulates signal 144 to produce a pre-transmission signal145, which is provided to signal modifier 122. Signal modifier 122modifies pre-transmission signal 145 in accordance with the one or morequality indicators received from demodulator 129 via quality indicationsignal 143. Signal modifier 122 may include control logic and a vectormodulator. The control logic determines a modification in accordancewith the one or more quality indicators. For example, quality indicationsignal modifier 122 may calculate a complex weighting based on thequality indicators. The control logic may also estimate the location ofthe time boundaries as well as other data. Signal modifier 122 modifiesa signal 145 by applying the determined modification in accordance witha time boundary to produce a set of modified pre-transmission signals146. Signal modifier 122 may include one or more modifiers that modify asignal or may instruct one or more other modifiers to modify a signal.As an example, a vector modulator of signal modifier 122 may modulate aphase of a signal. As an example, signal modifier 122 may instruct apower amplifier to modify the amplitude of signals.

A modified pre-transmission signal may comprise, for example, a basebandsignal, an IF signal, or an RF signal. Modified pre-transmission signal146 is sent to transmitter 128, which forwards modified pre-transmissionsignals 146 to transmit antenna 125. Transmit antenna 125 sends acombined signal based on modified pre-transmission signals 146.

Alterations or permutations such as modifications, additions, oromissions may be made to communication device 120 without departing fromthe scope of the invention. For example, communication device 120 mayhave more, fewer, or other modules. Moreover, the operations ofcommunication device 120 may be performed by more, fewer, or othermodules. Additionally, operations of communication device 120 may beperformed using any suitable logic comprising software, hardware, otherlogic, or any suitable combination of the preceding.

FIG. 5 is a block diagram of one embodiment of a transmitter system 200that may be used with communication device 120 FIG. 4. Transmittersystem 200 includes a baseband subsystem 210, a signal modifier 220, aradio subsystem 230, one or more power amplifiers 241, 242, 243, and244, and one or more antenna elements 251, 252, 253, and 254 coupled asshown.

Baseband subsystem 210 sends a pre-transmission signal 260, a qualityindication signal 270, and a time boundary signal 272 to signal modifier220. Signal modifier 220 includes vector modulator 221 and control logic222. Control logic 222 determines a modification in accordance with oneor more quality indications of quality indication signal 270, andprovides instructions for performing the modulation. As an example,control logic 222 may instruct vector modulator 221 to modulate a phaseof a signal. As another example, control logic 222 may instruct poweramplifiers to modify the amplitude of signals. Control logic 222 alsoestimates the locations of the time boundaries. Control logic 222provides instructions to apply the modifications in accordance with atime boundary. The modifications may be applied such that onemodification is applied per time period, for example, per power controlgroup. According to one embodiment, control logic 222 may use timeboundary signal 272 to determine the location of the time boundary.

Radio subsystem 230 receives the modified pre-transmission signal fromsignal modifier 220, and converts the received pre-transmission signalinto radio frequency (RF) signals, which are provided to poweramplifiers 241 through 244. Power amplifiers 241 through 244 eachreceive an RF modified pre-transmission signal and amplify the signalsfor transmission. Power amplifiers 241 through 244 provide the amplifiedsignals to antenna elements 251 through 254. Although transmitter system200 is shown as having four antenna elements 251 through 254 and fourcorresponding power amplifiers 241 and 244, transmitter system 200 mayhave any number of antenna elements and any number of power amplifiers.Each antenna element sends its respective RF modified pre-transmissionsignal to produce a transmitted signal.

Alterations or permutations such as modifications, additions, oromissions may be made to transmitter system 200 without departing fromthe scope of the invention. For example, transmitter system 200 may havemore, fewer, or other modules. Moreover, the operations of transmittersystem 200 may be performed by more, fewer, or other modules.Additionally, operations of transmitter system 200 may be performedusing any suitable logic comprising software, hardware, other logic, orany suitable combination of the preceding.

FIG. 6 is a block diagram of one embodiment of a signal modifier 500that may be used with any suitable communication device 20 such ascommunication device 20 a,c. Signal modifier 500 includes control logic502, an analog-to-digital (A/D) converter 504, a vector modulator 506,and one or more digital-to-analog (D/A) converters 508 and 509 coupledas shown. D/A converters 508 and 509 are coupled to one or more radiosubsystems 510 and 512 as shown. A D/A converter 508 and a radiosubsystem 510 may be associated with an antenna element.

According to the illustrated embodiment, signal modifier 500 receives apre-transmission signal. A/D converter 504 converts the pre-transmissionsignal to a digital form and forwards the digital pre-transmissionsignal to vector modulator 506. Control logic 502 establishes a qualityindicator and a time boundary. The quality indicator may be establishedby extracting the indicator from a quality indication signal or bydetermining the indicator independent of a quality indication signal.Control logic 502 determines a modification from the quality indicator,and provides instructions to vector modulator 506 for performing themodification. Control logic 502 provides instructions to apply themodifications in accordance with the time boundary. The time boundarymay be estimated by control logic or determined in response to anoptional time boundary signal. Modifications may be applied such thatone modification is applied per time period, for example, per powercontrol group.

According to one embodiment, control logic 502 determines a modificationfrom a quality indication signal by calculating a complex weighting. Thecomplex weighting is calculated by determining the appropriate weightingvalue associated with the in-phase signal component and the quadraturesignal component for an antenna element. As an example, if the phaserotation is being adjusted, the weighting value for the in-phase signalcomponent may be different from the weighting value for the quadraturesignal component. As another example, if the power ratio is beingadjusted, the weighting value for the in-phase signal component and theweighting value for the quadrature signal component may besimultaneously increased or decreased for a given antenna element inparallel. As yet another example, if the total power of the transmittedsignal is being adjusted, the weighting value for the in-phase signalcomponent and the weighting value for the quadrature signal componentmay be simultaneously increased or decreased for all of the antennaelements in parallel.

According to the embodiment, control logic 502 instructs vectormodulator 506 to perform the modification by providing the complexweighting values to vector modulator 506. Vector modulator 506 splitsthe pre-transmission signal into multiple pre-transmission signals.Vector modulator 506 applies the complex weighting to at least a subsetof the pre-transmission signals to modify the subset of pre-transmissionsignals based on the complex weighting values. D/A converters 508through 509 convert the pre-transmission signals to analog form. Radiosubsystems 510 through 512 convert the pre-transmission signals into anRF form. The signals may be forwarded to power amplifiers and respectiveantenna elements.

Alterations or permutations such as modifications, additions, oromissions may be made to signal modifier 500 without departing from thescope of the invention. For example, signal modifier 500 may have more,fewer, or other modules. Moreover, the operations of signal modifier 500may be performed by more, fewer, or other modules. Additionally,operations of signal modifier 500 may be performed using any suitablelogic comprising software, hardware, other logic, or any suitablecombination of the preceding.

FIG. 7 is a block diagram of another embodiment of a signal modifier 700that may be used with any suitable communication device 20 such ascommunication device 20 a,c. Signal modifier 700 includes one or moreA/D converters 710 and 715, one or more filters 720 and 725, a vectormodulator 730, control logic 740, one or more combiners 750 and 755, andone or more D/A converters 760 and 765 coupled as shown. D/A converters760 and 765 are coupled to one or more radio subsystems 770 and 780 asshown. A combiner 750 and 755, a D/A converter 760 and 765, and a radiosubsystem 770 and 780 may correspond to a given antenna element of anantenna.

According to the illustrated embodiments, A/D converter 710 converts abaseband in-phase signal component to a digital form, and A/D converter715 converts a baseband quadrature signal component to a digital form.Control logic 740 determines modification instructions from one or morequality indicators, and forwards the instructions to vector modulator730. Vector modulator 730 splits the in-phase and quadrature signalcomponents into a number of signals. Vector modulator 730 modifies thedigital signals according to the instructions. For example, vectormodulator 730 may apply complex weighting values to the in-phase andquadrature signal components associated for each antenna element.Combiners 750 and 755 combine the in-phase and quadrature signalcomponents of the modified pre-transmission signals. D/A converters 760and 765 convert the modified pre-transmission signals to analog form andforward the pre-transmission signals to radio subsystems 770 and 780.

Alterations or permutations such as modifications, additions, oromissions may be made to signal modifier 700 without departing from thescope of the invention. Signal modifier 700 may have more, fewer, orother modules. For example, one or more A/D converters 710 or 715, oneor more filters 720 and 725 may be omitted such that signal modifier 700receives digital signals. As another example, combiners 750 and 755 mayreceive signals from D/A converters 760 and 765 and operate to combineanalog signals. Moreover, the operations of signal modifier 700 may beperformed by more, fewer, or other modules. Additionally, operations ofsignal modifier 700 may be performed using any suitable logic comprisingsoftware, hardware, other logic, or any suitable combination of thepreceding.

FIG. 8 is a block diagram of one embodiment of a vector modulator 600that may be used with any suitable communication device 20 such ascommunication device 20 a,c. Vector modulator 600 includes a filter 610,in-phase signal adjusters 620 through 630, quadrature signal adjusters640 through 650, and combiners 660 through 670 coupled as shown. Anin-phase signal adjuster 620 through 630, a quadrature signal adjuster640 through 650, and a combiner 660 through 670 may be associated withan antenna element of an antenna.

According to the illustrated embodiment, filter 610 dividespre-transmission signals into in-phase and quadrature components.In-phase signal adjusters 620 through 630 and quadrature signaladjusters 640 through 650 receive complex weighting values from controllogic. In-phase signal adjusters 620 through 630 apply the complexweighting to the in-phase component of the pre-transmission signals, andquadrature signal adjusters 640 through 650 apply the complex weightingto the quadrature component of the pre-transmission signals. Theapplication of the complex weighting produces modified pre-transmissionsignals. Combiners 660 and 670 add the respective modifiedpre-transmission signals.

Alterations or permutations such as modifications, additions, oromissions may be made to vector modulator 600 without departing from thescope of the invention. Vector modulator 600 may have more, fewer, orother modules. For example, combiners 660 and 670 may be omitted.Moreover, the operations of vector modulator 600 may be performed bymore, fewer, or other modules. For example, the operations of filter 610may be performed by more than one filter, where one filter filters an Ichannel signal component and another filter filters a Q channel signalcomponent. Additionally, operations of vector modulator 600 may beperformed using any suitable logic comprising software, hardware, otherlogic, or any suitable combination of the preceding.

FIG. 9 is a flowchart illustrating one embodiment of a method formodifying a signal in accordance to a quality indicator that may be usedwith any suitable communication device 20 such as communication device20 a of FIG. 1. The method begins at step 800, where a firstcommunication device 20 communicates with a second communication device20. First communication device 20 waits for a time boundary at step 802.Modulating a signal in accordance with a time boundary may synchronizemodification of the signal with a quality indicator describing the linkquality in response to the modification. First communication device 20adjusts a modulation feature associated with antenna elements of firstcommunication device 20 to modulate a transmitted signal in accordancewith the time boundary at step 804. First communication device 20establishes a quality indicator describing the quality of communicationat step 808. For example, first communication device 20 may extract thequality indicator from a quality indication signal sent by secondcommunication device 20 or may calculate the quality indicatorindependent of any quality indication signal.

First communication device 20 determines a modification according to theadjustment and the quality indicator at step 812. For example, if thequality indicator indicates that the adjustment improved the quality ofcommunication, the modification may operate to enhance the adjustment.If the quality indicator indicates that the adjustment did not improvethe quality of communication, the modification may operate to change theadjustment.

First communication device 20 waits for a next time boundary at step814. The modification is applied to modulate a transmitted signal inaccordance with the next time boundary at step 816. If communicationdevices 20 continue to communicate at step 820, the method returns tostep 808, where first communication device 20 establishes a qualityindicator describing the quality of communication. If communicationdevices 20 do not continue to communicate at step 820, the methodproceeds to step 824, where communication is terminated. Aftercommunication is terminated, the method terminates.

Alterations or permutations such as modifications, additions, oromissions may be made to the method without departing from the scope ofthe invention. The method may include more, fewer, or other steps.Additionally, steps may be performed in any suitable order withoutdeparting from the scope of the invention.

FIG. 10 is a flowchart illustrating an example method for modifying asignal in accordance to a quality indication signal that may be usedwith any suitable communication device 20 such as communication device20 a of FIG. 1. First communication device 20 receives a power controlsignal from second communication device 20 at step 910. According to theCDMA protocol, a power control signal indicates either an up value or adown value for a given time period. An up value represents an indicationthat first communication device 20 should increase the total power ofits transmitted signal. A down value represents an indication that firstcommunication device 20 should decrease the total power of itstransmitted signal. According to one embodiment, the particular value ofa power control signal may be referred to as including a power controlbit, which represents either the up or down values in binary form.

Signal modifier 32 of first communication device 20 establishes that thepower control signal has reached a steady state at step 920. The powercontrol signal can reach a steady state in any suitable manner. Forexample, the power control signal may have a consecutive sequence ofvalues of up-down-up or down-up-down. The phase rotation associated withan antenna element is adjusted in one direction in accordance with atime boundary at step 930. For example, signal modifier 32 may calculatea complex weighting to change the phase rotation and provide the complexweighting to signal adjusters for the antenna element, which adjust thephase rotation according to the complex weighting.

Signal modifier 32 determines whether the power control signal indicatesthat first communication device 20 should decrease the total power ofits transmitted signal at step 940, which may be represented by a downvalue. If second communication device 20 received the transmitted signalwith increased total power, indicating that the communication is beingoptimized, second communication device 20 sends a down value in asubsequent power control signal. First communication device 20 maycontinue to attempt to optimize the phase rotation for the antennaelement and simultaneously reduce the total power of the transmittedsignal.

If the power control signal indicates a decrease for the total power atstep 940, then the phase rotation adjustment may have been effective andthe method proceeds to step 960. Signal modifier 32 establishes that thepower control signal has reached a steady state at step 960. Signalmodifier 32 changes the phase rotation associated with that antennaelement in the same direction in accordance with a time boundary at step970. If there is a next antenna element at step 975, the method returnsto step 940, where signal modifier 32 repeats the method for the nextantenna element. If there is no next antenna element at step 975, themethod terminates.

If the power control signal does not indicate a decrease for the totalpower at step 940, then the phase rotation adjustment may not have beeneffective and the method proceeds to step 950. Signal modifier 32changes the phase rotation associated with the antenna element in theopposite direction in accordance with a time boundary at step 950. Ifthere is a next antenna element at step 955, the method returns to step920, where signal modifier 32 repeats the method for the next antennaelement. If there is no next antenna element at step 955, the methodterminates.

Alterations or permutations such as modifications, additions, oromissions may be made to the method without departing from the scope ofthe invention. The method may include more, fewer, or other steps.Additionally, steps may be performed in any suitable order withoutdeparting from the scope of the invention.

FIG. 11 is a flowchart illustrating another example method for modifyinga signal in accordance to a quality indication signal that may be usedwith any suitable communication device 20 such as communication device20 a of FIG. 1. First communication device 20 receives a power controlsignal from second communication device 20 at step 990. According to oneembodiment, the power control signal may comprise a CDMA power controlsignal. Signal modifier 32 of first communication device 20 establishesthat the power control signal has reached a steady state at step 1000.The power control signal can reach a steady state in any suitablemanner. The phase rotation associated with an antenna element is changedin a one direction in accordance with a time boundary at step 1010.

Signal modifier 32 determines whether the power control signal indicatesthat first communication device 20 should decrease the total power ofits transmitted signal at step 1020, which may be represented by a downvalue. An instruction to decrease power may indicate that thecommunication is being optimized. If the power control signal does notindicate a decrease for the total power at step 1020, then the phaserotation adjustment may not have been effective and the method proceedsto step 1030. Signal modifier 32 changes the phase rotation associatedwith the antenna element in the opposite direction in accordance with atime boundary at step 1030, and the method returns to step 1020.

If the power control signal indicates a decrease for the total power atstep 1020, then the phase rotation adjustment may have been effectiveand the method proceeds to step 1040. Signal modifier 32 changes thephase rotation associated with that antenna element in the samedirection in accordance with a time boundary at step 1040. Signalmodifier 32 determines whether the power control signal indicates thatfirst communication device 20 should decrease the total power of itstransmitted signal at step 1050. If the power control signal indicates adecrease for the total power at step 1050, then the phase rotationadjustment may have been effective and the method returns to step 1040,where signal modifier 32 changes the phase rotation associated with thatantenna element in the same direction. If the power control signal doesnot indicate a decrease for the total power at step 1050, the methodproceeds to step 1060. The phase rotation is changed in accordance witha time boundary to optimize communication at step 1060. An optimum phaserotation may be obtained by taking the average of the phase rotations ofstep 1040. The method then proceeds to step 1065.

If there is a next antenna element at step 1065, the method returns tostep 1000, where signal modifier 32 repeats the method for the nextantenna element. According to one embodiment, the method may be repeatedfor each antenna element to obtain an overall optimum for multipleantenna elements. If there is no next antenna element at step 1065, themethod terminates.

Alterations or permutations such as modifications, additions, oromissions may be made to the method without departing from the scope ofthe invention. The method may include more, fewer, or other steps.Additionally, steps may be performed in any suitable order withoutdeparting from the scope of the invention.

FIG. 12 is a flowchart illustrating an example method for calculatingthe complex weighting that may be used with any suitable communicationdevice 20 such as communication device 20 a of FIG. 1. According to theembodiment, the complex weighting may be calculated by adjusting thephase rotation associated with each antenna element. Values for thepower control bits may be used to determine a phase rotation, andconsequently, a complex weighting.

According to the embodiment, first communication device 20 maycommunicate with second communication device 20 according to a CDMAprotocol. First communication device 20 sends a signal of power controlgroups (PCGs) having at least a first PCG and a second PCG, for example,adjacent PCGs, in such a manner that the power associated with the PCGsare at substantially the same level. Phase rotation Phi represents thephase rotation of the second antenna element relative to the firstantenna element in the first PCG. Phase rotation Phi+Delta representsthe phase rotation of the second antenna element relative to the firstantenna element in the second PCG, where Delta represents a phaserotation offset. The phase rotation offset Delta provides fordetermining the direction of the phase rotation between the antennaelements that may improve the quality of communication. Secondcommunication device 20 sends a power control signal having powercontrol bits for the PCGs. A power control bit may have a particularvalue for each time period. For example, the time period for the CDMAand the WCDMA protocols is 1.25 msec and 666 μsec, respectively.

The method begins at step 1100, where a phase rotation associated withthe first antenna element is initialized at first communication device20. A phase rotation offset Delta is introduced for the second PCGrelative to the first PCG in accordance with a time boundary at step1110. The phase rotation offset Delta provides for determining thedirection of the phase rotation between the antenna elements that mayimprove the quality of communication. First communication device 20transmits a signal based on the introduced phase rotation offset tosecond communication device 20 at step 1112. Second communication device20 sends a power control signal based on the received signal. Firstcommunication device 20 receives the power control signal at step 1114.

The complex weighting may be calculated from power control bitsassociated with the PCGs at steps 1120 through 1140. First communicationdevice 20 determines whether values of the power control bit for twotime periods, for example, adjacent time periods such as the two mostrecent time periods, are same at step 1120. If the values for the powercontrol bit are the same, the method proceeds to step 1130. The totalpower of the transmitted signal is adjusted in accordance with a timeboundary while maintaining the phase rotation for the first antennaelement, that is, maintaining Phi, at step 1130. The total power may beadjusted while maintaining the phase rotation by appropriatelycalculating a new complex weighting. The method then proceeds to step1145.

If the values for the power control bit differ at step 1120, the methodproceeds to step 1140. The phase rotation for the antenna elements, thatis, Phi, is adjusted in accordance with a time boundary whilemaintaining total power of the transmitted signal at step 1140. Thephase rotation may be adjusted while maintaining the total power byappropriately calculating a new complex weighting. The method thenproceeds to step 1145.

If there is a next antenna element at step 1145, the method returns tostep 1110, where a phase rotation offset is introduced for the nextantenna element. If there is no next antenna element at step 1145, themethod terminates.

Alterations or permutations such as modifications, additions, oromissions may be made to the method without departing from the scope ofthe invention. The method may include more, fewer, or other steps.Additionally, steps may be performed in any suitable order withoutdeparting from the scope of the invention.

FIG. 13 is a flowchart illustrating another example method forcalculating a complex weighting that may be used with any suitablecommunication device 20 such as communication device 20 a of FIG. 1.According to the embodiment, the complex weighting may be calculated byadjusting the power ratio and the phase rotation associated with eachantenna element to optimize a transmitted signal. The power ratio mayrefer to the ratio between the required transmission power for a weakerantenna element and the required transmission power for a strongerantenna element. An element detection threshold may be considered beforeadjusting any phase rotation or power ratio for the antenna elements.Based on the threshold values, the phase rotation may be adjusted toconverge to a substantially optimal phase rotation value. Havingdetermined the substantially optimal phase rotation value, the powerratio value for the antenna elements may be calculated until asubstantially optimal power ratio value is reached. The process isiterative and may be interrupted at any time to change any parameter,such as the phase rotation or the power ratio.

The method begins at step 1200, where the current power ratio for theantenna elements of first communication device 20 is determined. Firstcommunication device 20 determines whether the power ratio is below apredetermined threshold at step 1210. For example, the power ratiothreshold may be within a range of two to ten, such as between four andeight, such as approximately six. If the power ratio is not below thepredetermined threshold at step 1210, then the method proceeds directlyto step 1240.

If the power ratio is below the predetermined threshold, then the methodproceeds to step 1220 to tune the phase rotation. The phase rotation ischanged to find a substantially optimal value at step 1220. Firstcommunication device 20 determines whether the phase rotation issubstantially optimal at step 1230. If the phase rotation is notsubstantially optimal, the method returns to step 1220, where the phaserotation is changed in accordance with a time boundary to find asubstantially optimal value. If the phase rotation is substantiallyoptimal, then the method proceeds to step 1240.

At step 1240, the power ratio is changed to find an optimal value. Theoptimal value of a power ratio may optimize the transmission powerdistribution among the antenna elements. First communication device 20determines whether the power ratio is substantially optimal at step1250. If the power ratio is not substantially optimal, the methodproceeds to step 1240, where the power ratio is changed in accordancewith a time boundary to find an optimal value. If the power ratio issubstantially optimal, then the method proceeds to step 1255. If thecommunication is to continue at step 1255, the method returns to step1200, where the power ratio for the antenna elements of firstcommunication device 20 is determined. If the communication is toterminate at step 1255, the method terminates.

Alterations or permutations such as modifications, additions, oromissions may be made to the method without departing from the scope ofthe invention. The method may include more, fewer, or other steps.Additionally, steps may be performed in any suitable order withoutdeparting from the scope of the invention.

FIG. 14 is a flowchart illustrating another example method forcalculating a complex weighting that may be used with any suitablecommunication device 20 such as communication device 20 a of FIG. 1. Thecomplex weighting may be calculated by adjusting the power ratio and thephase rotation associated with each antenna element. Values for thepower control bit may be used to determine the proper phase rotation andpower ratio. The power ratio associated with the antenna elements may beadjusted after the phase rotation associated with an antenna element isadjusted.

According to the embodiment, first communication device 20 maycommunicate with second communication device 20 according to a CDMAprotocol. First communication device 20 sends a signal of power controlgroups (PCGs) having at least a first PCG and a second PCG, for example,adjacent PCGs, in such a manner that the power associated with the PCGsare at substantially the same level. Power ratio Lambda represents thepower ratio associated with the first PCG between a first antennaelement and a second antenna element. Power ratio Lambda+Zeta representsthe power ratio associated with the second PCG between the first antennaelement and the second antenna element, where Zeta represents the powerratio offset introduced between the first and second PCG. The powerratio offset Zeta may provide a mechanism to determine the direction ofchanging power ratio between the antenna elements that may improve thequality of communication.

The method begins at step 1300, where a phase rotation and a power ratioassociated with a first antenna element of first communication device 20is initialized. At step 1310, phase rotation offset Delta is introducedfor PCGs such as adjacent PCGs in accordance with a time boundary. Asignal is transmitted from first communication device 20 to secondcommunication device 20 based on the phase rotation offset. Secondcommunication device 20 sends a power control signal based on the signalfrom first communication device 20.

First communication device 20 determines whether values such as the mostrecently received values for the power control bit are same at step1320. If the values for the power control bits are the same, the methodproceeds to step 1330. The total power of the transmitted signal isadjusted in accordance with a time boundary while maintaining the phaserotation for the antenna element at step 1330. The power ratio for theantenna elements may also be maintained. The method then returns to step1310, where phase rotation offset Delta is introduced for PCGs.

If the values for the power control bits differ, the method proceeds tostep 1340. The phase rotation for the antenna elements is adjusted inaccordance with a time boundary while maintaining the total power of thetransmitted signal at step 1340. The power ratio for the antennaelements may also be maintained. First communication device 20determines whether the adjusted phase rotation is substantially optimalat step 1345. The optimal value of an phase rotation optimizes therelative phase of the transmitted signal among antenna elements given afixed power ratio. If the phase rotation is not substantially optimal,then the method returns to step 1310, where phase rotation offset Deltais introduced for PCGs. If the phase rotation is substantially optimal,then the method proceeds to step 1350.

Power ratio offset Zeta is introduced for PCGs such as adjacent PCGs inaccordance with a time boundary at step 1350. First communication device20 determines whether values such as the most recently received valuesfor the power control bit are the same at step 1360. If the values forthe power control bit differ, the method proceeds to step 1370. Thepower ratio for the antenna element is adjusted in accordance with atime boundary while maintaining total power of the transmitted signaland maintaining the phase rotation for the antenna elements at step1370. The method then proceeds to step 1350.

If the values for the power control bits are the same, the methodproceeds to step 1380. The power of the transmitted signal is adjustedin accordance with a time boundary while maintaining the power ratio andthe phase rotation for the antenna element at step 1380. Firstcommunication device 20 determines whether the track is lost at step1390. If the track is not lost, then the method proceeds to step 1395.If communication is to continue at step 1395, the method returns to step1350, where power ratio offset Zeta is introduced for PCGs. Ifcommunication is to terminate at step 1395, the method terminates.

If the track is lost at step 1390, then the method proceeds to step1397. If communication is to continue at step 1397, the method returnsto step 1310, where phase rotation offset Delta is introduced for PCGs.If communication is to terminate at step 1397, the method terminates.

Alterations or permutations such as modifications, additions, oromissions may be made to the method without departing from the scope ofthe invention. The method may include more, fewer, or other steps.Additionally, steps may be performed in any suitable order withoutdeparting from the scope of the invention.

FIGS. 15 and 16 are diagrams illustrating one embodiment of a slidingwindow technique for determining a time boundary corresponding to aquality indicator. As an example, the technique is described using aCDMA system, where a quality indicator refers to one or more powercontrol bits (PCB), a time period refers to a power control group (PCG),and a time boundary refers to a PCG boundary. The technique, however,may be used with any suitable communication system that sends qualityindicators at times determined in accordance with time boundaries.

Referring to FIG. 15, diagram 1500 illustrates extracted or detectedquality indication signals comprising power control bits. The powercontrol bits are indexed from i=0 to x−1, where x=2*PCGTI*SR, PCGTI isthe time interval of a power control group, and SR is the sampling rateof the signals. The indices may be repeated from i=0 to x−1 during a PCGboundary estimation time T, where T=2^(n)* x/SR, and n is an integergreater than, for example, four. The indexed power control bits arereordered according to the indices into an indexed frame.

Referring to FIG. 16, diagram 1600 illustrates PCG time intervalsdivided into power control groups 1512 with PCG boundaries 1514. Themaximum time interval of adjacent samples should be smaller than theminimum time interval of adjacent indexed power control bits. The powercontrol bits may be scrambled and randomly located in a PCB block 1520of a power control group 1512. For example, power control bits of apower control group 1512 may be scrambled by three or four bits of adecimated long code and located in a PCB block 1520 comprising the firsttwo-thirds of the power control group 1512. Theoretically, a PCB block1520 corresponds to a PCG boundary 1514. In actual systems, however,there are factors that spread the power control bits out of PCB block1520, as shown by arrows 1522 representing power control bits. Factorsmay include noise from the system, quantization effects, and inaccuratedetection of the power control bits.

A sliding window technique may be used to identify the most likelylocation of PCB block 1520. According to the technique, a sliding window1530 is defined. A sliding window 1530 refers to a duration that isapproximately equivalent to that of a PCB block 1520. At an initialiteration, sliding window 1530 a is set at a starting sample point, suchas a point with i=0, and the number of power control bits within slidingwindow 1530 a is determined. The number may be determined by countingthe number of detected PCB pulses. For a next iteration, sliding window1530 is moved to a next sampling index point to yield sliding window1530 b, and the number of power control bits within sliding window 1530b is determined. For a next iteration, sliding window 1530 is moved to anext sampling index point to yield sliding window 1530 c, and the numberof power control bits within sliding window 1530 c is determined.Sliding window 1530 may be moved any suitable length of time, such asover two PCG time intervals.

Sliding window 1530 with the largest number of power control bits mayidentify the most likely location of PCB block 1520. Once PCB block 1520has been identified, a PCG boundary 1514 for the power control group1512 that include the PCB block 1520 may be identified.

Alterations or permutations such as modifications, additions, oromissions may be made to the technique without departing from the scopeof the invention. The technique may include more, fewer, or other steps.Additionally, steps may be performed in any suitable order withoutdeparting from the scope of the invention.

Certain embodiments of the invention may provide one or more technicaladvantages. A technical advantage of one embodiment may be that amodification may be determined according to a quality indicator. Themodification may be applied to signals transmitted by multiple antennaelements, which may improve the quality of the transmitted signals.

While this disclosure has been described in terms of certain embodimentsand generally associated methods, alterations and permutations of theembodiments and methods will be apparent to those skilled in the art.Accordingly, the above description of example embodiments does notdefine or constrain this disclosure. Other changes, substitutions, andalterations are also possible without departing from the spirit andscope of this disclosure, as defined by the following claims.

To aid the Patent Office and any readers of any patent issued on thisapplication in interpreting the claims appended hereto, applicants wishto note that they do not intend any of the appended claims to invokeparagraph 6 of 35 U.S.C. § 112 as it exists on the date of filing hereofunless the words “means for” or “step for” are used in the particularclaim.

1. A method for determining a power control group boundary, comprising:receiving at a communication device a plurality of samples of a signal,the samples comprising a plurality of power control groups, each powercontrol group corresponding to a time period; repeating for apredetermined number of iterations: setting a window at a point of asample; determining a number of power control bits within the window atthe point; and sliding the window to a point of a next sample;identifying a point at which the window has the largest number of powercontrol bits; and determining a power control group boundary inaccordance with the window at the identified point.
 2. The method ofclaim 1, wherein the duration of the window is equivalent to theduration of a power control bit block.
 3. The method of claim 1, whereinthe duration of the window is equivalent to two-thirds of the durationof the power control group.
 4. The method of claim 1, whereindetermining the number of power control bits within the window at thepoint further comprises counting a number of power control bit pulseswithin the window at the point.
 5. The method of claim 1, wherein thepower control bits are spread out in response to at least one factor. 6.A system for determining a power control group boundary, comprising: aninput operable to receive a plurality of samples of a signal, thesamples comprising a plurality of power control groups, each powercontrol group corresponding to a time period; and control logic coupledto the input and operable to: repeat for a predetermined number ofiterations: set a window at a point of a sample; determine a number ofpower control bits within the window at the point; and slide the windowto a point of a next sample; identify a point at which the window hasthe largest number of power control bits; and determine a power controlgroup boundary in accordance with the window at the identified point. 7.The system of claim 6, wherein the duration of the window is equivalentto the duration of a power control bit block.
 8. The system of claim 6,wherein the duration of the window is equivalent to two-thirds of theduration of the power control group.
 9. The system of claim 6, whereinthe control logic is further to determine the number of power controlbits within the window at the point by counting a number of powercontrol bit pulses within the window at the point.
 10. The system ofclaim 6, wherein the power control bits are spread out in response to atleast one factor.
 11. A system for determining a power control groupboundary, comprising: means for receiving at a communication device aplurality of samples of a signal, the samples comprising a plurality ofpower control groups, each power control group corresponding to a timeperiod; means for repeating for a predetermined number of iterations:setting a window at a point of a sample; determining a number of powercontrol bits within the window at the point; and sliding the window to apoint of a next sample; means for identifying a point at which thewindow has the largest number of power control bits; and means fordetermining a power control group boundary in accordance with the windowat the identified point.
 12. A method for determining a power controlgroup boundary, comprising: receiving at a communication device aplurality of samples of a signal, the samples comprising a plurality ofpower control groups, each power control group corresponding to a timeperiod; repeating for a predetermined number of iterations: setting awindow at a point of a sample, the duration of the window beingequivalent to two-thirds of the duration of the power control group;determining a number of power control bits within the window at thepoint by counting a number of power control bit pulses within the windowat the point, the power control bits being spread out in response to atleast one factor; and sliding the window to a point of a next sample;identifying a point at which the window has the largest number of powercontrol bits; and determining a power control group boundary inaccordance with the window at the identified point.